Stalactite repair from scratch

[ChrisB]

But as the OP I was more interested in a possible repair where part of the stal was missing.

Those posts, about the repairs when the bits were available, were in the context of "how to fix them to the existing stal". The difficult part of that joint is the existing stal, because you have no choice about what it is, so they are just as relevant for attaching a new bit as for an original bit. In fact, if araldite will hold the weight of an original bit of stal, it will certainly be adequate to hold a relatively light dummy stal until it get calcited over.